NGN as an evolved network framework based on packet switching has attracted more and more attention. Telecommunication Standardization Sector of the International Telecommunications Union (ITU-T) and other regional standardization organizations such as the European Telecommunications Standards Institute (ETSI), the Alliance for Telecommunications Industry Solution (ATIS), and the like carry out general studies and standardization on the NGN framework model, service and relevant areas.
NGN is capable of supporting multi-access of a network. When a mobile user terminal performs multi-access, it is required to ensure service continuity, as well as to reduce authentication signaling between the mobile user terminal and an NGN network. There are 5 scenarios of multi-access defined in the NGN network.
Wherein there is a scenario, in which a user has multiple access modules that access a same access node, so as to achieve higher speed, offer faster data transmission and optimized experience, and enhance utilization rate of radio resources. When the user accesses the same nodes simultaneously, it is required to protect privacy and integrity of data between different access modules and the network access node, and in order to avoid interferences different access modules, different access modules of the terminal should use different keys. The terminal may generate different keys through performing authentication respectively between the NGN network and different access modules.
This however increases signaling interactions between the user terminal and the NGN network, which doubtlessly hinders the speed with which the user terminal accesses the network, resulting in vast waste of air interface resources which are already in shortage.